1. Field of the Invention
The present invention relates to a golf ball that has a plurality of dimples on the surface of a transparency cover containing a very small amount of pigment or dyestuff such that the shadows of dimples projected through the cover are in discord with the original positions of the dimples. Thus, especially, in the case of circular dimples, the shapes of shadows of edges of the dimples are revealed as irregular round polygons due to diffused reflection of light in the surface of the cover of the golf ball, in order that the golf ball can be more easily discriminated at a distance in a golf course than a golf ball made using a conventional method.
2. Description of the Related Art
In general, golf balls can be classified according to their structure into a two piece golf ball consisting of a single core and a single cover, a three piece golf ball consisting of dual core and a single cover, a three piece golf ball consisting of a single core and double cover, a four piece golf ball consisting of dual core and double cover, a four piece golf ball consisting of triple core and a single cover, a four piece golf ball consisting of a single core and triple cover, etc. In the past, many golfers used three piece wound golf balls manufactured by winding a stretched rubber thread on a tube of liquid or solid core and covering it with a cover. However, such golf balls lack durability and are manufactured using complicated processes and there are currently very few companies producing such golf balls. Solid cores of two piece, three piece, and four piece golf balls are made from a cis-1,4-polybutadiene rubber which is cured by a co-cross-linking agent, such as an unsaturated carboxylic acid or a metal salt thereof, with the aid of organic peroxide, wherein the rubber may be partially blended with another resin. The core mixture may be blended with an inorganic compound, such as zinc oxide, to control the specific gravity and assist the reaction of the co-cross-linking agent. In addition, various organic or inorganic compounds may be used in the core mixture as fillers or reinforcement materials. An inorganic or organic pigment or dyestuff may be used for coloring the cores, if required.
Meanwhile, in the past, balata rubber was used as a material for the covers of the above-described golf balls. However, ionomer resin is mainly used for the cover at present, owing to its strong physical properties and good durability against chemicals.
Recently, various cover materials, for example, urethane resin or other synthetic resins, or mixtures of these materials, have been used. In a general method of manufacturing a colored golf ball, the above-described cover material is mixed and treated with a suitable organic or inorganic pigment or dyestuff.
In addition to the method of mixing and treating the cover material with a coloring agent, a colored golf ball can be manufactured by coloring the core by adding a pigment or dyestuff or by coating the surface of the core with a paint of a desired color, and covering the colored core with a transparent cover such that the color of the core can be seen through the transparent cover.
Conventional golf balls are usually white and visually monotonous. Because such conventional white golf balls are similar, when 3-4 players play in a field, it is difficult for the players to quickly find their own golf ball in the field after being hit by a golf club.
To overcome this drawback, the colored golf balls are used instead of white golf balls. For example, fluorescent orange golf balls can be used in a field covered with snow because the fluorescent orange golf balls can be easily found in the white snow. In addition to fluorescent orange golf balls, golf balls in various colors are available. However, the appearances of these colored golf balls, which have turbid colors because they are made by merely adding a pigment or a dyestuff to their cover, are not graceful. In addition, such a colored golf ball cannot be easily found if it is buried in its surroundings, such as the green, soil, and others after flying and landing.
There are golf balls available with transparent covers or transparent covers containing a small amount of a fluorescent material. The transparent cover of a golf ball allows the color of the core and a logo or a number printed on the core to be seen so that the color of the core and the logo or the number printed on the core do not change over a long time, and therefore the graceful appearance of the golf ball can be maintained. However, since the core of such a golf ball is colored by adding a pigment or dyestuff or by being coated with a paint and a number or a logo is printed on the surface of the core to be seen through the cover (in general golf balls, a logo or a number is printed on their cover), the color of the golf ball is not distinct when in flight, and the landing point of the golf ball cannot be quickly found. This is because colored golf balls are darker than white golf balls and absorb a larger amount of light and reflect a smaller amount of light than white balls when flying.
This is also related to the phenomenon that dimples on the surface of the cover of a golf ball are seen well at a certain angle and not at other angles (because the angle of reflection of light varies depending on the observation point). This phenomenon may be attributed to that the color of the core and the logo printed on the core are shown through the cover, on the surface of which more regular reflections of light than diffused reflections occur.
Accordingly, in order to easily predict the landing point of such a colored golf ball flying with a back spin, more diffused reflections should be induced on the golf ball to scatter a larger amount of light. Hence, an object that can reflect light can be attached to the cover of the golf ball or the surface of the cover. However, such an object greatly lowers the repulsive elasticity of the golf ball and markedly shortens the carry distance.